Wave set-up on coral reefs .2. Set-up on reefs with various profiles

All available laboratory data for wave set-up on two dimensional reef profiles of various shapes have been compared with data from an idealised horizontal reef with a steep reef-face (Gourlay, 1996). The data is generally well represented by a relationship between the relative set-up parameter <(eta)over bar (r)>/T root gH(o) and the submergence parameter (<(eta)over bar (r)> + h(r))/H-o and the relative set-up on reef profiles of natural form is found to be less than that observed on the idealised horizontal reef. The important influences of reef-rim slope and variable water depths on the reef-top have been investigated and some methods for allowing for them are suggested. Comparison of data for irregular waves with that for regular waves has led to the development of a simple method for estimating the effects of wave groups upon the magnitude of the steady state mean wave set-up <(eta)over bar (r)>. The results of the analyses are applied to the determination of wave set-up and its effects at three specific coral reef sites.